Intelligent Use of LAPS • By • Ed Szoke • 16 May 2001

LAPS •A system designed to: •Exploit all available data sources •Create analyzed and forecast grids •Build products for specific forecast applications •Use advanced display technology … All within the local weather office

Why do analysis in the local office?

® THE CONCEPT OF THE LOCAL DATA BASE IS CENTRAL TO FUTURE OPERATIONS … THE MOST COMPLETE DATA SETS WILL ONLY BE AVAILABLE TO THE LOCAL WFO. THE NEW OBSERVING SYSTEMS ARE DESIGNED TO PROVIDE INTEGRATED 3-D DEPICTIONS OF THE RAPIDLY CHANGING STATE OF THE ENVIRONMENT. ” -Strategic plan for the modernization and associated restructuring of the National Weather Service

Data Acquisition and Quality Control

Local Data • Local Data may be defined as that data not entering into the National Database • Sources – Highway Departments •Many States with full or partial networks – Agricultural Networks •State run, sometimes private – Universities and Other Schools •Experimental observations – Private Industry •Environmental monitoring – State and Federal Agencies •RAWS

Problems with Local Data •Poor Maintenance •Poor Communications •Poor Calibration Result >Inaccurate, Irregular, Observations

Quality Control Methods •Gross Error Checks Rough Climatological Estimates •Statistical Models Buddy Checking •Dynamical Models Use of meso-beta models

Requirements for QC Scheme •Runnable in weather offices on small workstations •Adaptable to ongoing model improvement •Adaptable to daily variations in model skill

•SOLUTION: The KALMAN FILTER •Adaptable to small workstations •Accommodates models of varying complexity •Model error is a dynamic quantity within the filter, thus the scheme adjusts as model skill varies Requirements for QC Scheme (cont.)

LAPS Overview •LAPS Grid –Horizontal Resolution = 10 km –Vertical Resolution = 50 mb –Size: 61 x 61 x 21

The blue colored data are currently used in AWIPS LAPS. The other data are used in the "full-blown" LAPS and can potentially be added to AWIPS/LAPS if the data becomes available.

Sources of LAPS Information •The LAPS homepage provides access to many links including: •What is in AWIPS LAPS?

• LAPS analysis discussions are near the bottom of: • • Especially noteworthy are the links for • Satellite Meteorology • Analyses: Temperature, Wind, and Clouds/Precip. • Modeling and Visualization – A Collection of Case Studies Analysis Information

3-D Temperature •Interpolate from model (RUC) •Insert sonde, RASS, and ACARS if available –3-Dimensional weighting used •Insert surface temperature and blend upward –depending on stability and elevation •Surface temperature analysis depends on –METARS, Buoys, and LDAD –Gradients adjusted by IR temperature

3-D Clouds  Preliminary analysis from vertical ® soundings ” derived from METARS and PIREPS •IR used to determine cloud top (using temperature field) •Radar data inserted (3-D if available) •Visible satellite used

3-D CLOUDS

LAPS Snow Cover and Precip. Type

LAPS 3-D Water Vapor (Specific Humidity) Analysis • Interpolates background field from synoptic-scale model forecast • QCs against LAPS temperature field (eliminates possible supersaturation) • Assimilates RAOB data • Assimilates boundary layer moisture from LAPS Sfc Td analysis • Scales moisture profile (entire profile excluding boundary layer) to agree with derived GOES TPW (processed at NESDIS) • Scales moisture profile at two levels to agree with GOES sounder radiances (channels 10, 11, 12). The levels are hPa, and above 500 • Saturates where there are analyzed clouds • Performs final QC against supersaturation

Products Derived from Wind Analysis

Case Study Example •An example of the use of LAPS in convective event •14 May 1999 •Location: DEN-BOU WFO

Quote from the Field • "...for the hourly LAPS soundings, you can go to interactive skew-T, and loop the editable soundings from one hour to the next, and get a more accurate idea of how various parameters are changing on an hourly basis...nice. We continue to find considerable use of the LAPS data (including soundings) for short- term convective forecasting."

Case Study Example • On 14 May, moisture is in place. A line of storms develops along the foothills around noon LT (1800 UTC) and moves east. LAPS used to diagnose potential for severe development. A Tornado Watch issued by ~1900 UTC for portions of eastern CO and nearby areas. • A brief tornado did form in far eastern CO west of GLD around 0000 UTC the 15th. Other tornadoes occurred later near GLD.

NOWRAD and METARS with LAPS surface CAPE 2100 UTC

For this part we will go to a web presentation to show this example in detail

This example showed how LAPS can be used for Nowcasting. LAPS is also ideal for initializing a local model, since the analysis should capture features better than just simply using a background lower resolution model.

Why Run Models in the Weather Office? •Diagnose local weather features to enhance conceptual models –sea/mountain breezes –modulation of synoptic scale features •Take advantage of high resolution terrain data to downscale national model forecasts –orography is a data source!

•Take advantage of unique local data –radar –surface mesonets •Have an NWP tool under local control for scheduled and special support •Take advantage of powerful/cheap computers Why Run Models in the Weather Office? (cont.)

Some examples of a local model are shown next. The topography of Colorado leads to a wide variety of weather...and a local model can be of great value to helping to forecast the resulting weather. Some forecast problems include: -orographic precipitation -"Denver Cyclone" -"Longmont Anticyclone"

SFM forecast showing details of the orographic precipitation, as well as capturing the Longmont anticyclone flow on the plains

LAPS analysis for 1500 UTC

•You can see more about our local modeling efforts at LAPS Summary

The increasing amount of output for the forecaster to look at from the different models (such as a local model) can be overwhelming and difficult to comprehend during an operational forecast shift. So it is desirable to explore new ways to examine model and analysis grids. One new way we are working on is called "D3D" for Display in 3 Dimensions (versus "D2D"). Our D3D work can be further viewed on our homepage at:

D3D example showing an isosurface of relative humidity

Example of Powerful Sounding Tool in D3D